Scuba diving is not regulated in the US by any government agencies. The industry has adopted certification requirements for divers and is self-regulating. The recommended maximum diving depth for a “recreational diver” is 130 feet. Technical divers and commercial divers do dive to deeper depths (approaching 1000 ft.) using special air mixes and equipment.
At sea level, the atmospheric pressure varies slightly, but is about 14.7 pounds per square inch, or more conveniently 1 atmosphere (1 atm). When descending into water, the pressure down at 33 feet in sea water, or 34 feet in fresh water, increases by an additional atmosphere, so the pressure is 2 atm. The increase in pressure is a linear function, so at 66 feet, the pressure is 3 atm, etc. The pressure at 130 feet is about 5 atm, or about 75 psi.
Most recreational divers breathe from a “regulator” that is held in the mouth by biting down on a mouthpiece. The regulator is attached to a tank of compressed air. Most divers are taught from the very beginning classes to take their regulator out of their mouth and throw it to the side, simulating having the regulator pulled out of their mouth. They are instructed to retrieve it and put it back in their mouth. Most everyone has no trouble with this task. This skill is required for a diver to gain certification.
Divers typically wear a buoyancy compensation device (commonly called a BCD) which is an inflatable vest that is connected to the air tank, and is used to adjust buoyancy. Most divers also attach other equipment to their BCD, such as regulator gauges, knives, safety sausages, topside signaling devices, dive slates for written communication, etc. Underwater communication system described in the disclosure below may be connected to the BCD with a retractable lanyard in some embodiments.
At least some embodiments of the disclosure described below are directed to underwater communication systems, underwater speakers, underwater microphone assemblies and associated methods.